As the technology for the charged particle beam application system, the inventors of the present invention have examined the following technology.
The landing angle of the charged particle beam (hereinafter, simply referred to as “beam”) means the angle between a normal of an object to which a beam is irradiated and an optical axis of a beam. More specifically, when a beam is irradiated to a sample, the angle between a normal of the sample and the optical axis of the beam indicates the landing angle to the sample, and when a beam is irradiated to a detector, the angle between a normal of the detection plane and the optical axis of the beam indicates the landing angle to the detector. If a detection plane and a sample are parallel to each other, the landing angle to the detector and the landing angle to the sample are equal. If not parallel, the relation between the angles is measured to know it in advance. Note that, in the case where the detector is composed of a plurality of components (for example, the case where detection is made in combination with a mark and a detector), the landing angle can be defined by an angle between a normal of a plane of a component easy to be measured or defined (for example, mark) and an optical axis of a beam.
In the charged particle beam lithography system, the charged particle beam observation system and the charged particle beam processing system, the small landing angle is desired in general. This is because, in the case where the landing angle is large, the beam irradiation position is shifted when the height of a sample is changed, which affects the lithography, image observation and processing position. Also, the landing angle of the beam is largely related to an optical property such as beam blur in some cases, and an optical axis of the beam with large landing angle frequently deviates from the center of lens. Furthermore, the landing angle is often increased when the beam is deflected. Therefore, for the beam lithography, image observation and processing with high accuracy, a highly accurate measurement of the landing angle of the beam is indispensable.
In the conventional landing angle measurement in the lithography system, beam is deflected while changing the height and a relative landing angle at the time of deflection is obtained from the change in deflection width depending on the height.
Meanwhile, in the field of the lithography, a lot of expectations are placed on the electron beam lithography system because it has an advantage that the high resolution can be achieved due to its short wavelength. However, it also has a problem that the throughput is lower than other optical lithography systems. In such a circumstance, for the solution of the problem of throughput unique to the electron beam lithography system, a multi electron beam lithography system has been proposed (for example, “Journal of Vacuum Science and Technology”, 2000, B18(6), pp. 3061 to 3066 (Non-Patent Document 1)). In this method, since the area to be exposed at one time is wider than that of the conventional method, the throughput can be improved.